Cloud Functions updates too late firestore - node.js

Question

im new at cloud functions
i just want to disable my targets after countdown end. this function works correctly but updates after 3 min after function finished
what am i missing?
const functions = require("firebase-functions");
const admin = require('firebase-admin');
admin.initializeApp();
const db = admin.firestore();
exports.timecontroller = functions.firestore.document("DigitalTargets/{digitalTargetID}").onCreate((snap, context) => {
const id = snap.id
const date = new Date(snap.data().endDate.toDate())
var countDownDate = date.getTime();
var myfunc = setInterval(function () {
var now = new Date().getTime();
var timeleft = countDownDate - now;
if (timeleft < 0) {
db.collection("DigitalTargets").doc(id).update({ isActive: false })
clearInterval(myfunc);
}
}, 1000);
})

Answer 1

Since you pay for the time that your Cloud Functions code executes, the container tries to execute your code and terminate as quickly as possible. Unless you tell it otherwise, that means that it terminates the code as soon as the final statement before the closing } executes.
But since you are executing an asynchronous operation with your setInterval call, the code actually needs to continue to run after the closing }.
To allow that you'll need to return a promise that resolves when the code is complete. Something like:
exports.timecontroller = functions.firestore.document("DigitalTargets/{digitalTargetID}").onCreate((snap, context) => {
const id = snap.id
const date = new Date(snap.data().endDate.toDate())
var countDownDate = date.getTime();
return new Promise((resolve, reject) => { // 👈 This tells Cloud Functions to wait
var myfunc = setInterval(function () {
var now = new Date().getTime();
var timeleft = countDownDate - now;
if (timeleft < 0) {
db.collection("DigitalTargets").doc(id).update({ isActive: false })
clearInterval(myfunc);
resolve(); // 👈 This tells Cloud Functions that you're done
}
}, 1000);
})
})
I recommend reading (and watching the videos in) the Firebase documentation on asynchronous behavior in Cloud Functions.